In recent years, a digital camera or digital video camera has been reduced in size and weight, and a camera having a communication function has been increasingly used and developed.
For example, there is a system in which a display for displaying images is provided to a remote controller capable of intercommunicating with a camera, start or stop of image capturing by the camera is controlled by an operation of the remote controller, and the captured image can be displayed on the display of the remote controller.
Note that examples of the existing techniques that disclose a system in which a camera operation is capable of being controlled by using a remote controller include Patent Literature 1 (Japanese Patent Application Laid-open No. 2015-127920).
In the system in which the camera is controlled by the remote controller, for example, an image captured by the camera is transferred to the remote controller and displayed on a display unit (display) on the remote controller side, so that a user as an operator of the remote controller can execute an instruction such as image recording start or stop processing.
Each of the camera and the remote controller is equipped with a battery (battery cell) and, with the power supply from the battery, executes various types of data processing such as image capturing processing, image display processing, and further communication processing between the remote controller and the camera.
However, image transfer, image display processing, and other types of data communication processing consume a large amount of power. Meanwhile, the capacitance of the battery mounted to the camera or the remote controller is limited, and reducing the power consumption as much as possible is demanded.